House Democrats are prepared to open multiple investigations of President Trump when they take control in January but are wary of immediately pursuing impeachment — working to balance the demands of an energized base with the voters they need in the next election.

Trump’s Wednesday threat to adopt a “warlike posture” in response to any probes of his presidency or personal finances angered rank-and-file Democrats, some of whom argued they should get “very aggressive” and try to beat Trump at his own game.

“The American people like and respect fighters, and they have elected us to put a check on the executive branch,” Rep. Ro Khanna (D-Calif.), who said he has been talking to his colleagues about pushing ahead with investigations of Trump, starting with his tax returns.

But Khanna stopped short of calling for impeachment proceedings against the president, an explosive move that party leaders worry could create peril in 2020 for lawmakers who represent districts the president carried in his first bid.

Though they have not determined precisely which investigations to launch when they take the majority next year, Democrats are expected to scrutinize Trump administration policies on immigration, education and health care, and to examine his personal finances and potential connections to Russia.

“For those who want impeachment, that’s not what our caucus is about,” House Minority Leader Nancy Pelosi (D-Calif.) told PBS’s “NewsHour” on Tuesday before her party clinched the majority. She said she would not move to impeach Trump unless at least some Republicans were on board.

Pelosi added that she will wait for the outcome of the special counsel investigation but noted that a call for impeachment “would have to be bipartisan, and the evidence would have to be so conclusive.”

But Trump threatened Wednesday to turn the Republican-led Senate on Democrats who cross him.

“They can play that game, but we can play it better, because we have a thing called the United States Senate,” the president said. “I could see it being extremely good for me politically because I think I’m better at that game than they are, actually, but we’ll find out.”

Meanwhile, Democratic leaders’ resistance to embracing an impeachment effort could cause a significant backlash among the party’s restive liberal flank.

According to a Washington Post-Schar School poll Tuesday of voters in battleground districts, nearly two-thirds of those who voted for Democratic House candidates want Congress to begin impeachment proceedings, which could lead to Trump’s removal from office.

But party leaders said they need to be judicious about using new committee gavels to strike at Trump — knowing that their actions could energize an angry Republican base if they beat him up indiscriminately.

“We have to be as strategic and methodical as we possibly can,” said one senior Democratic aide who spoke on the condition of anonymity to discuss internal strategy. “If subpoenas go flying, and lawsuits go flying, you’re in the mud with [Trump] — and that’s what he wants.”

On Wednesday, key Democrats said it would be premature to begin impeachment proceedings, adding that such a conversation should take place after special counsel Robert S. Mueller III has completed his inquiry. Rep. Jerrold Nadler (N.Y.), ranking Democrat on the House Judiciary Committee, told CNN that it is “way too early” to discuss that step.

Some moderate Democrats urged restraint more broadly, saying the focus should be on governing.

Rep. Conor Lamb (D-Pa.), whose district voted for Trump by 20 points in 2016, told CNN that he did not wish to go after the president’s tax returns. And Rep. Jimmy Gomez (D-Calif.) said that those seeking to inflict revenge on Trump are “wrong,” tweeting that it is not “payback time” but “time to govern.”

Even Rep. Richard E. Neal (D-Mass.), ranking Democrat on the Ways and Means Committee, who intends to push for Trump’s tax returns, said in an interview that launching investigations “cannot be the sole purpose of this election.”

“Proportionality is everything,” Neal said.

To start, Democrats are expected to focus their scrutiny on areas in which they think Trump’s actions are demonstrably unethical or unconstitutional and on administrative decisions that affect Americans’ security and livelihoods, officials said.

“Where people go wrong is in seeing oversight in this really small prism of ‘How are you going to go after Donald Trump?’ That’s not it at all,” said Ashley Etienne, a spokeswoman for Pelosi, who is expected to be elected House speaker.

“We’re going to run two lanes: protecting and defending the Constitution, and addressing the things we’re fighting for, like access to health care and the skyrocketing cost of prescription drugs,” she said.

The House Judiciary Committee is likely to take the lead on health care, beginning with an investigation of Attorney General Jeff Sessions’s refusal to defend the Obama-era Affordable Care Act against a lawsuit from Republican-led states.

Nadler, who is set to become the panel’s chairman next year, tweeted late Tuesday: “@realDonaldTrump may not like it, but he and his administration will be held accountable to our laws and to the American people.”

Neal said he intends to obtain them using a 1924 law that gives heads of the congressional tax-writing committees the right to request any American’s tax returns. The panel could then make them public with a simple majority vote.

Trump and other conservatives have suggested that the White House might fight any effort by Democrats to obtain the returns, setting up a possible constitutional challenge that tests a nearly 94-year-old law.

Treasury Secretary Steven Mnuchin, who is fiercely loyal to Trump, recently told the New York Times that he would review any request from lawmakers with the relevant officials at the Treasury Department.

Trump also could try to exert executive privilege over the material in a way that attempts to block it from being revealed.

Waters has requested — and as the committee head, could subpoena — records that could dislodge closely held details of Deutsche Bank’s relationship with the Trump Organization.

The German bank lent Trump more than $400 million during a decade-long real estate buying spree that began in 2005, largely through its private wealth management office, not the commercial banking division that typically handles real estate.

Schiff also has pledged to scrutinize “serious and credible allegations” that Russians may have laundered money through Trump’s businesses, potentially giving the Kremlin leverage over the president.

And he plans to investigate Russian election interference more fiercely than have Republicans, whom Schiff accused of using the intelligence panel to discredit Mueller’s investigation.

“We’ll fill in the gaps on the Russia investigations,” Rep. Eric Swalwell (D-Calif.), a member of the House Intelligence Committee, told NBC on Wednesday.

On the Intelligence Committee, Schiff wants to scrutinize Trump’s efforts to strike a nuclear deal with North Korea and the administration’s willingness to cut deals with China, despite the national security threats the country poses.

Democrats on his panel also plan to investigate Saudi Arabia and the Oct. 2 killing of Saudi journalist Jamal Khashoggi, which could further complicate Trump’s efforts to pursue weapons deals with the kingdom.

On the Judiciary Committee, Nadler is expected to dedicate attention to the rise of white supremacy and the proliferation of firearms — national debates that have been exacerbated by deadly shootings at a Pittsburgh synagogue last month and at Marjory Stoneman Douglas High School in Parkland, Fla., in February.

Nadler also recently told the New York Times that he would scrutinize the FBI’s review of sexual assault allegations against Supreme Court Justice Brett M. Kavanaugh, which Democrats have complained was too limited.

To dig into Trump’s allegiances abroad, Democrats may scrutinize Trump’s hotel in downtown Washington — and the foreign clients who frequent it.

Foreign dignitaries from Kuwait, the Philippines, Saudi Arabia and elsewhere have patronized the hotel. Such transactions have prompted two lawsuits alleging that Trump is violating the Constitution’s prohibition on presidents taking “emoluments,” or payments, from foreign states.

Such an investigation probably would be handled by the House Oversight Committee, where incoming chairman Elijah E. Cummings (D-Md.) already plans to look at the “zero tolerance” policy that caused the detention of thousands of migrant children who were separated from their families while trying to cross the U.S.-Mexico border, and the administration’s intention to include a citizenship question on the 2020 Census.

The panel wants to balance those inquiries with renewed attention to the administration’s widely criticized response to Puerto Rico in the aftermath of Hurricane Maria, and the continuing water crisis in Flint, Mich.

Although panel Democrats have not yet determined how many investigations they will open in January, any number would be “going up from zero,” one Democratic committee staff member said, complaining that “literally not one document, not one subpoena was issued to the White House” by Republicans.

Karoun DemirjianKaroun Demirjian is a congressional reporter covering national security, including defense, foreign policy, intelligence and matters concerning the judiciary. She was previously a correspondent based in The Post's bureau in Moscow. Follow

Tom HamburgerTom Hamburger is an investigative reporter on the national desk of The Washington Post. He has covered the White House, Congress and regulatory agencies, with a focus on money and politics. Follow

Gabriel PogrundGabriel is 2018 Stern Fellow at The Washington Post. He previously covered politics and national news at the Sunday Times of London. Follow